Datasheet
AT30TSE752A/754A/758A [DATASHEET]
Atmel-8854G-DTS-AT30TSE752A-754A-758A-Datasheet_102014
10
5. Device Operation
Commands used to configure and control the operation of the AT30TSE752A/754A/758A are sent to the device from the
Master via the serial interface. Likewise, the Master can read the temperature data from the AT30TSE752A/754A/758A
via the serial interface; however, since multiple slave devices can reside on the serial bus, each slave device must have
its own unique 7-bit address so that the Master can access each device independently.
For the AT30TSE752A/754A/758A, the first four MSBs of its 7-bit address are the device type identifier and are fixed at
1001 for temperature sensor and 1010 for Serial EEPROM. The remaining three LSBs correspond to the states of the
hard-wired A
2-0
address pins.
Example: If the A
2-0
pins are connected to GND, then the 7-bit device address would be 1001000 or 1010000.
In order for the Master to select and access the AT30TSE752A/754A/758A, the Master must first initiate a Start
condition. Following the Start condition, the Master must output the device address byte. The device address byte
consists of the 7-bit device address plus a Read/Write (R/
W) control bit, which indicates whether the Master will be
performing a Read or a Write to the AT30TSE752A/754A/758A. If the R/
W control bit is a Logic 1, then the Master will be
reading data from the AT30TSE752A/754A/758A. Alternatively, if the R/
W control bit is a Logic 0, then the Master will be
writing data to the AT30TSE752A/754A/758A.
Table 5-1. AT30TSE752A/754A/758A Address Byte
Note: 1. See Section 10.5, “Software Write Protect” on page 40 for more information.
If the 7-bit address sent by the Master matches that of the AT30TSE752A/754A/758A, then the device will respond with
an ACK after it has received the full address byte. If there is an address mismatch, then the AT30TSE752A/754A/758A
will respond with a NACK and return to the idle state.
5.1 Temperature Measurements
The AT30TSE752A/754A/758A utilizes a band-gap type temperature sensor with an internal sigma-delta Analog-to-
Digital Converter (ADC) to measure and convert the temperature reading into a digital value with a selectable resolution
as high as 0.0625C. The measured temperature is calibrated in degrees Celsius; therefore, a lookup table or conversion
routine is necessary for applications that wish to deal in degrees Fahrenheit.
The result of the digitized temperature measurements are stored in the internal Temperature Register of the
AT30TSE752A/754A/758A, which is readable at any time through the device's serial interface. When in the normal
operating mode, the device performs continuous temperature measurements and updates the contents of the
Temperature Register (see Section 6.2, “Temperature Register” on page 17) after each analog-to-digital conversion.
The resolution of the temperature measurement data can be configured to 9, 10, 11, or 12 bits which corresponds to
temperature increments of 0.5C, 0.25C, 0.125C, and 0.0625C, respectively. Selecting the temperature resolution is
done by setting the R1 and R0 bits in the Configuration Register (see Section 6.3, “Configuration Register” on page 19).
The ADC conversion time does increase with each bit of higher resolution, so careful consideration should be given to
the resolution versus conversion time relationship. The resolution after device power-up or reset will revert to what was
previously selected using the NVR1 and NVR0 bits of the Nonvolatile Configuration Register bits prior to when the device
was powered-down or reset.
With 12 bits of resolution, the AT30TSE752A/754A/758A can theoretically measure a temperature range of 255C
(-128C to +127C); however, the device is only designed to measure temperatures over a range of -55C to +125C.
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Function Device Type Identifier Device Address Read/Write
Temp Sensor 1 0 0 1 A2 A1 A0 R/W
Serial EEPROM 1 0 1 0 A2 A1 A0 R/W
Software Write Protection
(1)
0 1 1 0 A2 A1 A0 R/W